3. The richest person in modern history, John D. Rockefeller Sr. was America’s first billionaire with an adjusted-for-inflation net worth exceeding $400 billion.
John Davison Rockefeller Sr. (b. 1839) was an American oil tycoon and industrialist during the late-19th and early-20th centuries. Born into an unremarkable family, John, along with his brother William and friend Samuel Andrews, founded Rockefeller & Andrews in their early 20s to attempt to break into the oil refining business. Growing and expanding respectably, in 1870 Rockefeller founded the Standard Oil Company. Profiting from the soaring costs of gasoline, Standard Oil, through highly unsavory and ruthless business strategies, successfully created a virtual monopoly over the American oil industry.
Controlling at its peak more than ninety percent of all oil in the United States, Standard Oil was ordered dismantled into thirty-four separate components by the Supreme Court in 1911 due to anti-trust violations. Although opening up the oil industry, this separation financially benefited Rockefeller, whose personal shares in the new spin-off companies, such as ExxonMobil and Chevron, exploded in value. Becoming the wealthiest man in America and the first billionaire in the nation’s history, Rockefeller’s peak net worth came just two years later in 1913, valued at $409,000,000,000 when adjusted for inflation.